Your spectator writes their name on a blank card, and THEY lose that card into the pack. They then write their partners name on a different card and that card gets lost in the pack too. You tell your spectator to think back to when they first met their partner and to imagine the two cards finding each other in the pack. Once they have done this you spread the cards and the two written on cards are right next to each other. You explain that the cards have found each other but you want to take things one step further.
The two cards get shuffled and lost back into the pack. You then ask your spectator what is the date of their anniversary. KEEP IN MIND this is AFTER the two cards have been shuffled into the pack. They tell you the date and you count down that number of cards, your spectator then turns over the next two cards and they are, the two written on cards.

A beautiful effect that will hit home with your spectators as it's so personal to THEM.